


Demonology for the Proactively Self-Destructive

by ThrallofPentacles



Series: The Summoner's Transformation [1]
Category: Original Work
Genre: Begging, Body Modification, Consensual Non-Consent, Creampie, Crying, Demon Summoning, Dirty Talk, Face-Fucking, Forced Crossdressing, Forced Feminization, Forced Orgasm, Height Differences, Humiliation, Lingerie, M/M, Misgendering, Orgasm Delay/Denial, Pain, Penis In Vagina Sex, Plot What Plot/Porn Without Plot, Safewords, Size Difference, Slut Shaming, Squirting, Succubi & Incubi, Transformation, Vaginal Fingering, Vaginal Sex, afab language, and a pinch of, and a reference to him growing breasts in the future, but it's pretty mild (Zin flicks and pinches his clit once), cis man given a vagina, seriously transmasc folks be careful reading this, sort of (Zin calls him a slut but that's about it), succubus becomes an incubus to match the summoner's preference
Language: English
Status: Completed
Published: 2020-10-19
Updated: 2020-10-19
Packaged: 2021-03-09 01:42:07
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,056
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27096736
Author URL: https://archiveofourown.org/users/ThrallofPentacles/pseuds/ThrallofPentacles
Summary: On page thirty-two of Demonology for the Proactively Self-Destructive, there’s a warning. Beware honeyed words, beware beautiful flesh—for a demon may offer your deepest desire, and you may give your very soul, but it will remain unfulfilled. A lot of words to put in an annotation above the spell to summon a succubus, but it boils down to this: she may look good, but she’ll destroy you before she gives you what you want.Dylan can’t read it without laughing. It’s such tripe, there’s no way whoever wrote it actually tried the spell. A cubus always gives you exactly what you want—that’s how it destroys you.
Relationships: Incubus/Summoner, Zin/Dylan
Series: The Summoner's Transformation [1]
Series URL: https://archiveofourown.org/series/2006842
Comments: 3
Kudos: 273





	Demonology for the Proactively Self-Destructive

_Demonology for the Proactively Self-Destructive_ came to Dylan in a deceptively ordinary way. He stumbled across it in the back of a used book shop, held together more by sheer spite than its fraying leather spine, for sale for two ninety-nine. He bought it on a lark and took it home, thinking it would be a fun way to kill a couple hours muttering in tongues and scaring the shit out of his neighbors.

He was twenty-three, single, and horny, so of course he started with the succubus. Sex with a supernaturally hot demon sounded well worth ignoring a cryptic warning. He set up a creepy magic circle—with lots of salt, because apparently demons couldn’t cross it. Whatever you say, book. There was a chant that Dylan fucked up two or three times, then finally managed to get right. He pricked the tip of his finger and let a drop of blood fall to the floor.

At first, he was convinced nothing had happened. He was so hazy from all the incense he’d lit that it took him a moment to realize that something was moving in the center of the circle. “Holy—” he blurted, and stumbled backwards so quickly that he tripped over his own coffee table. The succubus emerged in a flash of light and smoke and looked down at him in bemusement.

“Quite unholy, actually.”

Dylan’s mouth fell open. An actual honest-to-god demon had just… waltzed into his apartment. He looked down in a sudden panic, just to confirm that the circle was still there.

“Oh, yes.” The succubus gestured at it with the tip of her long, barbed tail. “I’m going to have to ask you to get rid of that, if you actually want to do anything.”

“Wh-what?”

“Unless you want to climb in with me? There isn’t much room in here. If you’d made it a little wider, then maybe we could make do…”

“Oh.” Dylan swallowed hard. His brain was still playing catch-up. He made a few aborted attempts to speak, then shook his head. “That’s—no. That would be really, really dumb.”

The succubus gave him an odd look. “You do realize you summoned a _cubus,_ don’t you? Why wouldn’t you want to—ah.” The confusion on her face cleared. “I see what the problem is.”

There was another flash of light. When it faded, the succubus was gone. In her place was the most beautiful man Dylan had ever seen. Long hair cascaded down his chest in silky black waves. His skin was a deep red and glossy where it caught the light, as if he’d been oiled. Firm muscle rippled beneath it. He was tall and broad-shouldered, with the same pointed tail as the succubus. But the place where Dylan’s eyes went, as if they were pulled there by some kind of magnet, was the massive cock that hung between the demon’s legs. He swallowed, his mouth suddenly very dry.

“Much better,” the man purred. His voice was rich and deep, and sent shivers down Dylan’s spine. “Come closer.”

Dylan was moving before he could think better of it, and when he realized what he was doing he froze in panic. “What are you—what the hell is this?”  
  


“I’m a cubus. Whether I manifest as a succubus or an incubus or something in between is entirely up to your preference.”

“But I’m not—”

The demon raised an eyebrow and pointedly looked down. Flushing, Dylan cupped his hands over his sweatpants, which had started to tent.

“Well, good luck with that little discovery. In the meantime, why don’t you come lend me your ear?”

“What are you going to do?” Dylan asked suspiciously.

“I thought you might like a bit of security,” the incubus said. “So, here it is—once we begin, the game will only stop if you say my true name. If you do, I vanish and everything goes back to normal. Feel free to burn the book and never think about it again… but I don’t think you will. After all, I know exactly what you want.”

Dylan had the uncomfortable feeling that the demon was looking right through him. He shifted from foot to foot, knowing that what he was about to do was a terrible idea, but… the few times he’d had sex before, it had always felt like something was missing. Now the answer was just a whisper and a pinch of salt away.

Screw it. He leaned in, shivering at the brush of the incubus’ lips against his ear as he whispered the name. Dylan would have called it unpronounceable, but he knew instinctively that he’d be able to say it if he needed to. Magic, he was starting to realize, was weird like that.

“If you’d like to scream my name without ending our game,” the demon went on, “you may call me Zin.”

Dylan nodded.

“Now, little fly.” Zin flashed a wicked smirk that made Dylan’s insides erupt into butterflies. “Step into my parlor.”

Dylan reached out with one toe… hesitated… and broke the circle of salt. He stepped back as Zin emerged, stretching himself with the predatory grace of a wolf. The demon was taller than him by almost a foot, and the difference made his heart race. He retreated until his back came up against the wall.

The incubus followed, putting his palms against the wall on either side of him and boxing him in. The tip of the demon’s cock brushed against his stomach, and one of his hands slipped under Dylan’s shirt. His knees buckled, and he would have fallen if he hadn’t grabbed Zin’s shoulders for balance.

“Do you like that? Hm?”

“I…” His voice was hoarse. “I think s— _ah!”_

Zin’s roaming fingers found his nipples and twisted. Dylan collapsed against him, and when the demon led him away from the wall and pushed him down on the couch, he didn’t resist. He lay there with his shirt rucked up to his chest as the incubus straddled him.

“This isn’t right, is it?” Zim tapped a finger against his chin. “You’re missing something.” Dylan, who was more turned on than he’d ever been in his life, made a noise of helpless confusion. The incubus grinned, showing off a pair of sharp canines. “Let’s try giving you something pretty to wear.”

Something hot clenched in the pit of Dylan’s stomach. His cock swelled. He trembled as Zin snapped his fingers, making his clothes disappear in a flash. And in their place…

Dylan whimpered at the sight of a thin, lacy bra cupping his chest. It was a pale, delicate shade of pink. He could see his nipples through the fabric, stiffened by his arousal.

“Go on,” Zin told him. “Look down.”

His sweatpants and briefs were gone, too. He could see his erection straining against more gauzy pink fabric. The panties could hardly contain it, they were so flimsy. His cheeks burning, Dylan glanced reluctantly up at Zin’s face.

The incubus’ mocking smile made his flush spread all the way down his chest. The demon palmed him through the panties, and he let out a little whine. “I think I get it now,” Zin said. He played with Dylan’s cock, running his hand along the shaft, teasing the tip, always with the thin fabric between them. “You want me to show you what a little slut you are.”

It was too much. “N-no!” he blurted. “I don’t, I—” His mind raced, searching for some way to release this heat building in his lower belly, something that would keep his dignity intact. “I want to fuck you.” He could do that, couldn’t he? Sink his dick inside this demon, assert himself...

Zin laughed. “With this?” He pulled the band of the panties down, and Dylan’s cock flopped free. “Well. I suppose you could try.”

Dylan spluttered indignantly. Sure, he wasn’t _huge,_ but he wasn’t exactly little either. He would have said as much, but the evil glint in the incubus’ eyes made him stay silent.

Sure enough, “There is _one_ condition.”

“C-condition?”  
  


“You’re going to suck me off first.”

“Oh.” Relief flooded him. He could handle that.

He lay back as the incubus settled in over his face. The demon’s dick was long and thick enough to make him self-conscious, so he took it into his mouth where he wouldn’t have to look at it anymore. Zin sighed with pleasure. “You have such a good mouth on you,” he said, petting Dylan’s hair. “It’s like you were made for this, slut.”

Dylan choked. The demon let out a harsh laugh and grasped his hair in his fist, fucking into his mouth while he spluttered. Zin’s thrusts were rough and erratic, and soon he leaned back with his eyes half-closed in concentration. He was close. All Dylan had to do was get him off, and then he could take him apart. Make him scream on his cock. Make him take it all back. Maybe he’d make Zin wear these fucking clothes.

Zin pulled out so suddenly that a bit of drool ran down Dylan’s chin. For a moment the demon’s full length hung in front of his face, swollen and flushed a red so dark it looked almost black. Then he sat back on his haunches and started to stroke himself.

“But I—”

“Aw, so disappointed.” Zin shook his head in bemusement. “Don’t worry, slut. You’ll get my cock as long as you’re good.”

“Stop calling me that!” Dylan snapped.

The incubus ignored him. He was too busy tugging Dylan’s panties down so that they bunched up halfway down his thighs. The demon’s eyes fluttered closed, and for a moment the only sound was the frantic slapping of skin on skin as he worked his cock. A shudder ran through him. He grabbed Dylan’s hips, lined himself up, and spurted all over his dick and balls.

Dylan yelped and flinched. Zin’s come was hot, and it tingled wherever it touched his skin. “What the hell was that?”

Zin didn’t answer. He held him down with one hand on his chest, and with the other he started to stroke Dylan’s cock. Soon it was covered in come, and the tingling feeling had spread all along his length. He moaned and went limp. It felt strange, almost like static, but it sent little tingles of pleasure jolting up his spine. With him compliant, Zin took his balls in his other hand, rubbing his come into them, too.

The feeling was so good, he was sure he must be getting even harder—but it didn’t feel like it. Every stroke seemed to make him softer, even as the fire in his belly got hotter and hotter. Dylan groaned, half in pleasure and half in confusion. He looked down and let out a sharp scream.

His cock still poked out of the top of his panties, and it was as hard as it had been since Zin pressed him against the wall—but now, it was no longer than a finger. His balls had shriveled up so much that he could hardly see them from this angle. Every time Zin pumped his hand along Dylan’s length, it shrank even further.

“What the fuck?!” He jolted upright and tried to scramble away.

Zin chuckled and swung a leg over his hips, pinning him against the couch. “You really thought _you_ could fuck _me?”_

“I—you—stop! Put it back!” A name tickled at the back of Dylan’s mind—but no. Not yet. Instead he fought with all his strength, and failed to shift Zin an inch.

“Do you want to try?” Zin asked, his voice dripping cruel amusement. “I’m not sure I’d feel this…” He flicked Dylan’s cock, now less than an inch long. As tiny as it was, the nerves hadn’t gone anywhere—mixed pain and pleasure exploded from the place the incubus had struck, and he moaned.

“You definitely can’t ejaculate.” Zin ran a finger all the way from the underside of Dylan’s cock to his asshole, to show him that his balls had completely disappeared. “I suppose I could lie down and let you rub your clit on my ass. Is that what you want, slut?”

“M-my—!” Tears sprang up in the corners of Dylan’s eyes. That was exactly what it looked like. Zin was still playing with it, though now he only needed one finger to tease the tiny nub of flesh. It was so sensitive that every light touch made him shiver.

“No,” Zin decided. “A slut like you couldn’t be satisfied with that. You were so desperate for my cock earlier…”

“I’ll suck you off!” Dylan’s voice shook with desperation. “Just put it back and I’ll do whatever you want!”

Zin only smiled. His finger dipped down beneath Dylan’s— _fuck!_ There was no other word for it. His clit. There was a long stretch of smooth skin beneath it, skin that tingled when the incubus touched it. He couldn’t suppress a little gasp at the sensation. Zin pressed his finger in harder, rubbing up and down between Dylan’s legs until he found a place where he could push _in—_

“Oh god!” Dylan’s eyes flew open in horror. He tried to squirm away, but he might as well have tried to get out from under a statue carved from iron. There was nowhere to go as Zin’s finger pressed into a vulnerable spot just under his clit, sinking deeper and deeper as something stretched and stretched and _broke._

“No!” he moaned. “Please, don’t—!” Too late. He felt it slide inside him, curling to rub against a long ridge of flesh at the front of this new hole that sent waves of heat pulsing through his body. There was no pain, but Dylan sobbed in embarrassment as the finger sank all the way into him, deep enough to touch something horribly sensitive in the depths of his… his…

“Much better.” Zin started to play with the hole, sliding in and out and teasing the entrance with the tip of his middle finger. “A slut like you needs a nice wet pussy.”

Tears ran down Dylan’s cheeks. He could feel heat building inside him, throbbing between his legs. Slick ran down from his hole to coat the insides of his thighs. “P-please put it back,” he whispered.

“Does my little toy want to know how to get his cock back?”

Dylan squeezed his eyes shut and nodded.

“Well, that’s easy.” The incubus leaned forward so that he could whisper in his ear. “It’ll wear off in a few hours. All you need to do… is not come until then.” He slipped another finger inside Dylan, making him yelp. “Of course, if you _do…_ you’ll stay like this forever.”

“St-stop, then!” Dylan tried to close his legs, but Zin was kneeling between them. “I can’t—you have to—”

“Oh, no. I’m going to do whatever I like to you. You say you’re not my filthy slut? Prove it.”

Zin started fucking two fingers in and out of Dylan’s pussy and rubbing his clit with his thumb. The sensation made Dylan’s back arch without his permission. His legs spread wider, and the panties slid down his legs to tangle his ankles together. He clenched his fists, willing his body to _stop—_ but he could feel his pussy clenching down on the demon’s fingers.

The incubus chuckled and drew back. This was Dylan’s chance to get out from underneath him, but he was so overwhelmed, it was all he could do to try and catch his breath. He was still struggling to pull himself together when Zin grabbed his hips and lifted him onto his lap.

Dylan gasped as his front pressed up against that hard, muscled chest. The skin there was silky smooth and hot to the touch. His legs spread over Zin’s, and before he could catch himself he ground his dripping cunt against one of the demon’s thighs.

“Look at this mess you’ve made. Such a dirty girl.” The shame of it burned, but Dylan still couldn’t stop. He slid up and down, grabbing desperately at Zin’s shoulders to keep his balance, making a filthy wet sound as he rubbed himself against the demon’s leg.

Zin laughed and gathered slick on his fingertips. He slipped his hands under the lacy bra, so that he could rub it into Dylan’s nipples. “Someone’s changed her tune.”

“Nnh!” Dylan’s clit throbbed. “Stop calling me that!” He sobbed in frustration and humiliation when Zin had to grab his hips again to keep him from humping his leg.

“Shh. I’ll need you to show me a _little_ self control, slut, if I’m going to give you what you want.”

Dylan’s head was hazy and his body felt like it was on fire, but he managed to stammer, “I w-want my cock back.”

“Aren’t you cute,” Zin cooed. He tweaked one of Dylan’s nipples through the bra, and a bolt of pleasure made him gasp. They were so sensitive… “Now, be a good girl and spread your legs for me.”

“I’m not—!” Dylan tried to protest, but his legs spread obediently over Zin’s lap. He looked down and shuddered at the sight of himself spread wide, still dressed in frilly lingerie, his cunt dripping onto the demon’s hard cock.

Zin still held him up by his hips. He guided him gently down until the tip of his dick teased at Dylan’s slit, making him squirm and cry out. “You want it, baby? You want me to fuck your pussy?”

Dylan could only moan.

“Say it for me.”

“P-please…”

“Please what?” The head of Zin’s cock pressed against his entrance, and his hips jerked in an effort to get it inside him. But the demon’s hold was too strong, and in his desperation he betrayed himself.

“Please fuck my pussy,” he whispered.

The hands on his hips eased him down. There was a brief, sharp pain as the head of Zin’s cock popped inside him, and then the wonderful tingling pressure of being filled. Dylan sank down onto the demon’s cock until he was sitting flush against his lap. His toes curled.

“Good girl.”

He hated the pleased little whimper that escaped him. He clung to the thought that it was only because Zin had finally filled that aching emptiness between his legs, and not the humiliating praise. It wasn’t much comfort.

He didn’t mean to, but he pressed himself against the demon’s chest. “This is where you belong,” Zin purred. Dylan could feel the words vibrating between their bodies. His hips ground down against the cock inside him. He started to rock himself back and forth, faster and faster, chasing the knot of heat building in his lower belly.

Reality snapped back into place just in time. He froze, remembering what the demon had done to him, and what he’d warned him would happen if he went over that edge. It would last another hour or so—he could take that. He had to take that. Then he’d get his dick back, and he could finally, _finally_ get release.

“My little slut is trying so hard, it’s adorable.”

Dylan shook his head helplessly, and Zin laughed. “Ride my cock, baby.”

He tried not to. He tried to remember why he needed to hold on, but he just couldn’t do it. His clit pulsed and throbbed. Dylan wrapped his arms around the back of the demon’s neck for leverage, and bounced himself up and down on the massive cock inside him. His ass slapped against Zin’s thighs, and the sound sent another rush of heat through him.

“Perfect. You’re such a good girl for me.” Zin squeezed his ass. “Say it.”

“Oh god!” He buried his face in the curve of the demon’s neck. “Please don’t make me.”

Zin pinched his clit. The jolt of pain was so sudden that he screamed. His pussy clenched, and the next thrust made him see stars. Dylan started to sob.

“Say it, slut.”

“I’m your good girl!” he moaned. The pain stopped in an instant, and hot shame flooded the pit of his stomach.

“You’re going to come for me, aren’t you?”

“N-no…”

“Yes.” Zin rubbed his clit with his thumb. Dylan writhed on his cock, his mouth gaping open as he fought against his building orgasm. “Don’t fight it. Come on my cock, slut.”  
  


“No!” Dylan’s vision started to blur. He looked down at himself. His chest bounced up and down as he rode Zin’s cock, jostling the frilly pink bra with every thrust. His legs were spread as wide as they could go. The panties were still tangled around his ankles. He felt so fragile, like a touch could shatter him.

Zin could see it too. He drove into him as deep as he could go, growling as he spilled hot come into Dylan’s pussy. One hand slipped under his bra to play with his nipple, and the other rolled his clit between his fingers. He moaned and sobbed and shook with the desperate need to come, but he held off.

Then Zin brought his lips to Dylan’s ear and whispered, “Come for me, baby girl.”

The words sent a bolt of liquid fire right to his clit. He trembled as the heat spread through his pussy, making it clench on Zin’s cock. He was helpless to stop it—all he could do was cling to the demon’s shoulders as the feeling shot through him and he lost control of his body. His eyes rolled back. A ringing sound filled his ears. He convulsed, his legs jerking and twitching, his hips still rocking frantically back and forth as he tumbled over the edge. Slick gushed out of him and into Zin’s lap.

Dylan collapsed against the demon’s chest. Even then, it still wasn’t over. For a long moment he couldn’t move, couldn’t think, could only listen to the heartbeat underneath his ear and shudder with every fresh wave of pleasure that shot through his clit. His new pussy fluttered around the cock that was still buried inside him.

Eventually, he came back to earth. Zin was looking down at him, an amused twinkle in his eyes. “Well? Have I given you what you wanted?”

He averted his eyes as he admitted, “Yes.”

Zin let out a self-satisfied hum and got to his feet, leaving a wrecked Dylan sprawled on the couch. “In that case, I suppose I’ll see you when you next summon me.”

Instantly, Dylan started clearing his plans for tomorrow. It must have shown on his face, because the incubus wagged a finger at him. “Not so eager, slut. I’m afraid you won’t be able to cast the spell again for a year and a day.”

“A—a _year?”_

“And a day.” Zin smirked at his obvious distress. “You’ll have to manage without me, until then. In the meantime, you are permitted— _encouraged,_ in fact—to find other men to give you what you need.”

Dylan flushed. “My… my pussy?”  
  


“Will remain as it is, unless you call my name and return yourself to normal.”

He nodded, still blushing furiously. Already his traitorous mind was calling up vivid images of himself going to bars, letting someone lead him into the bathroom and— “One last thing, before I go.” Zin pinched his nipple through his bra. The feeling was so sudden and intense that Dylan yelped. When he pulled the underwear off, he found that both nipples were red and slightly swollen, and so sensitive that just brushing against them made him hiss.

“What did you do?”

“Oh, just a little curse to remember me by. Every time you come, your chest will get a little bit bigger.” Zin’s eyes glittered with playful malice. “I look forward to seeing it, baby girl.”

The words struck Dylan like a punch in the gut. By the time he’d recovered enough to speak, Zin had vanished without a trace—except for the broken circle of salt on his floor. He shivered and sank back against the couch. A year and a day. He already felt so needy, how was he going to survive a year and a day?

His pussy throbbed. Dylan looked at the slick and come still smeared all over his thighs. He bit his lip, reached down, and started to tease himself.


End file.
